Manoj K. Choudhary

A Three-Dimensional Mathematical Model for Flow and Heat Transfer in Electrical Glass Furnaces

A three-dimensional mathematical model was developed for calculating joule heat release, glass flow, and heat transfer in electric glass furnaces. The model developed here allows for multiple electrodes, multiphase firing, and for the feeding and withdrawal of molten glass. The model is fairly general with respect to the arrangement of the electrodes, the firing pattern, and the choice of the boundary conditions, and it allows for the temperature dependence of the glass properties. The model was used to calculate electric potential, rate of heat release, flow pattern, and temperature distribution in the melting of flint and amber glasses in an all-electric melter with side-entering electrodes. The calculations were performed for the industrial conditions of pull, power, and the electric firing scheme. The bulk glass temperature was found to be very uniform with large temperature gradients near the boundaries. The calculated flow pattern was, in general, quite complex with several circulation loops. The temperature and the maximum velocity for the amber glass were found to be higher than the corresponding values for flint glass.

A modeling study of flow and heat transfer in an electric melter

Abstract A three-dimensional mathematical model was used to calculate flow and heat transfer in electric melting of a flint glass in an industrial scale melter. Calculations were performed for side- and bottom-entering electrodes. Results on rate of heat release, velocity, temperature, and residence time distribution were used to examine the influence of electrode orientation. The residence time distribution was obtained by solving the transient response to a step change in the tracer concentration. The results indicate that the electrode orientation had a significant effect on velocity and temperature distribution, mostly in the planes which contained the electrodes. In these planes it was observed that with the bottom-entering electrodes, the downward glass velocity near the wall was 10 to 20 times larger, but the side-entering electrodes resulted in a more uniform temperature distribution. In planes not containing electrodes, the overall flow pattern and temperature distribution were similar. Both cases were characterized by a high level of mixing and had very similar residence time distributions.